Diamond black onyx are the perfect pair! This fabulous modern cocktail ring features a 1.03 carat marquise cut diamond in 14 karat yellow gold. Set in protective prongs, the dazzling center diamond has a soft white hue and is accented by black onyx on the tapered band. The diamond color and sparkle pops against the black gemstones. A timeless, modern treasure. Shop More Onyx Diamond Jewelry.